Solid state transformer based hybrid microgrid architecture for increased solar PV penetration

Abstract

Increased penetration of rooftop solar PV is causing undesirable technical impacts on the distribution networks. It has been identified that several urban distribution transformers in Sri Lanka are exceeding fifty percent of the solar PV over the transformer capacity. Improving the hosting capacity of the existing distribution network has thus become a trending research topic in both local and international power systems industry. Among the identified technical impacts of high solar penetration are; voltage rise, harmonics and DC injection. The contribution of this study is focused on designing a new microgrid architecture that integrates the solid state transformer with zonal hybrid microgrids to mitigate the aforementioned issues. By utilizing the dc and ac ports of the solid-state transformer, the hybrid network can access the distribution system, which renders the coordinate management of the power and improves the power supply reliability. The designed solid state transformer controllers maintains the AC and DC feeder voltages. MATLAB/ Simulink platform was used to model and simulate the proposed network and to demonstrate how the proposed system has mitigated the power quality issues.